Endotracheal balloon catheter provided with inflation pressure regulating valve



Apnl 7, 1970 v. N. F. LOMHOLT 3,504,676

ENDOTRACHEAL BALLOON CATHETER PROVIDED WITH INFLATION PRESSUREREGULATING VALVE Filed June 13, 1967 I Y WRW X w- United States PatentU.S. Cl. 128-351 3 Claims ABSTRACT OF THE DISCLOSURE A respiratorycatheter in which the tube for delivering respiration air under pressureto a patients lungs is enclosed along a portion of its lower end with abladder of non-resilient material adapted to engage the patients tracheaand provide a seal preventing entry of vomit to the lungs, the bladderbeing connected with a separate source of air under lesser pressure thanthat delivered to the lungs by means of a pipeline connected with atwoway blocking valve disposed in the tube and controlled by therespiration air. The respiration air during the inhalation phase closesthe two-way valve and applies pressure to the outside of the bladder atthe downstream end to maintain the seal, whereas, during exhalation, theabsence of the respiration air pressure allows the two-way valve to opento enable the lower pressure air to provide suflicient inflation of thebladder for sealing purposes.

This invention relates to respiratory catheters of the type consistingof a tube for introducing air to the lungs of the patient, adapted to beintroduced in the trachea of the patient and provided with a tubesurrounding bladder to create a tightening in relation to the wall ofthe trachea, whereby the interior of said bladder is in connection witha separate pipe connected to a source of pressure.

It has been found to be most important in using respiratory catheters toobtain a really eifective tightening or construction therewith inrelation to the wall of the trachea and especially to maintain thetightening also during the expiration phase, more especially becausewhen treating unconscious patients, one may be in need of a breathingsecurity, i.e. a protection against any vomit that may arise and pushthrough the trachea and down to the lungs. In respiratory catheters suchas are known in the art, various types of tightening means for providingconstruction between the catheter and the trachea wall have been used,such as a vesicle or bladder made of a resilient material and,therefore, capable to be inflated against the trachea wall and therebyprovide tightening. It appears, however, that such a tightening in orderto be etficient under all conditions has to be provided at acomparatively high pressure, the resilient bladder for sealing purposesbeing constantly required to exert a pressure against the mucousmembranes of the trachea during both the inspiratory and exspiratorysure. Such a constant pressure against the trachea wall often has aharmful elfect on the mucous membranes of the wall, leading to adecrease of or eventually a cessation of the blood circulation in thearea in question.

The aim of the present invention is to provide a respiratory catheterapplicable to artificial respiration without such disadvantages as foundin prior art respiratory catheters. It is an object of the presentinvention to provide means with which to obtain an airtight closure ofthe trachea during both the inspiratory and expiratory phase ofartificial ventilation of the lungs without subjecting the mucosa of thetrachea to pressures harmful ice thereto. This is achieved according tothe present invention by a respiratory catheter tube which is providedWith a bladder comprised of a thin, preferably nonresilient foilmaterial with such dimensions that it can readily be brought intotightening abutment against the wall of the trachea without resilientdeformation of the bladder, and which communicates With a compressed airsource through a two-Way blocking valve disposed in the pipe throughwhich respiration air is supplied to the catheter tube, said blockingvalve being controlled by the pressure of the respiration air.

The invention will now be described with reference to the accompanyingdrawing, representing a longitudinal section view of a respiratorycatheter incorporating the principles of the present invention.

In the drawing is shown a respiratory catheter consisting of a cathetertube 1, which at one or its upper end is joined to a T-shaped tube 2,one branch of which is closed olf as by a cork 3, the main branch 4 ofthe tube serving as inlet nozzle for the respiration air to the cathetertube 1.

The opposite or lower end of the catheter tube is provided with anappropriate bent segment and has a bladder 5 secured on the outside ofsaid tube around said bent segment. The bladder may be supplied with airunder pressure through a duct 6 in the wall of the tube 1. From the ducta thin pipeline 7 leads into the main branch 4 of T-shaped tube 2 and isconnected to one end of an inflatable-collapsible blocking valve 8disposed in said main branch 4 as shown. The blocking valve 8 maycomprise two plane foil members 8 welded together along their rims tothus form a hollow inflatable-collapsible valve. A thin pipe 9 isconnected with the other end of the blocking valve and in turn outletsfrom the tube branch 4 to serve as an inlet nozzle for deliveringcompressed air to the bladder 5 from a source separate from thatsupplying the respiratory air.

The respiration air pressure applied is of course dependent on thepatient and on varying external circumstances and should normally be ofa pressure height corresponding to 20-70 cm. column of water, whereas,the air pressure in the bladder 5 may be maintained somewhat lower, egat a height corresponding to 16-20 cm. column of water. A pressure likethat cannot injure the mucous membranes of the trachea and the increaseof pressure caused by the respiration pressure does not exceed thepressure imposed on the rest of the air passage by the respiratorytreatment.

When using the catheter of the present invention, practically no forceis required for pressing the bladder 5 against the trachea wall and thepressure exerted within the bladder is consequently entirely utilized toprovide sealing. Moreover, the bladder tends, without alterations of theinternal pressure, to comply with any alteration of the dimensions ofthe trachea still without requesting a particular pressure application;thus it is possible to maintain pressure in the bladder at the lowestpossible level.

When using a blocking valve such as valve 8 to control pressure inbladder 5 with the opening and closing of the blocking valve in turnbeing controlled by the respiration pressure, a performance is achievedwhere the amount of air pressure introduced into the bladder 5 throughduct 6 from a separate source of compressed air at a lower pressure thanthe respiration air so as to fill and enlarge said bladder, such air isconfined in said bladder as soon as the respiration air under pressurebeing delivered through tube 1 rises. Thus the respiration air pressurecloses blocking valve 8 preventing entry or outflow of the air underlower pressure from bladder 5, with the respiration air itself exertinga pressure against the outside of the bladder at the lower part, i.e.,facing the lungs causing an increase of the abutting pressure of thebladder against the trachea. In the expiration periods, a rather low airpressure in the bladder is all that is required for proper operation ofthe bladder for tightening purposes. Such air pressure supply to thebladder during the expiration periods is substantially below a possiblyharmful pressure. During the expiration period, the absence of thehigher pressure air in branch 4 allows the blocking valve 8 to open orinflate and connection of the bladder 5 with the separate lower airpressure source occurs to thereby permit enlargement of the bladderagainst the trachea. Generally compressed air is used as pressure mediumand since the respiration pressure frequently is considerably higherthan the pressure required to provide breathing security, the confiningof the amount of compressed air introduced in the bladder will merelylead to a squeezing by the respiration pressure of the extremity of thebladder which turns downwards the lungs to an extent resulting in adecrease of the total volume of the bladder and the pipe connectedthereto, whereby the pressure will increase precisely as much asrequired to ensure the tightening.

As was indicated earlier, blocking valve 8 is located in branch 4 so asto provide an eflective control of the valve. This allows for autilization of the drop of pressure which occurs in the course of thepassage of the air between the entry orifice of the respiration tube 1and the valve 8. When, e.g., the respiration pressure decreases from itsmaximum value, an opening of the valve 8 will occur which allows a partof the volume of air in the bladder and which was compressed therein bythe externably located maximal respiration pressure, to escape, wherebythe pressure in the bladder for a short moment becomes too low to keepup a perfect sealing of the trachea against the respiration pressure notyet dropped to its minimum value. By virtue of this, during a shortmoment a passage will be produced along the mucous membranes and betweenthem and the bladder along which upward transport of phlegm and otherundesirable matter can take place, just as said trachea and adjacentorgans in the natural state always manage to remove such impurities. Theperfect sealing is, however, again provided when the respirationpressure drops right down to its minimal value and the separate lowerair pressure supply enlarges the bladder against the trachea.

What I claim is:

1. A respiratory catheter comprising a tube adapted to be introducedinto the trachea of a patient for delivery of respiration air underpressure to the patients lungs,

said tube having an upper entry end anda lower bent section, a bladderof thin, non-resilient material enclosing the bent section of said tubeand being secured thereto, said tube having a duct therein communicatingwith the interior of said bladder, an elongated in-flatablecollapsibleblocking valve disposed in said tube at the entry end thereof, a pipeline connecting one end of said blocking valve with said duct, and apipe connecting the opposite end of said blocking valve with a source ofair at a pressure lower than that of the respiration air, the pressureof respiration air flowing through said tube during inspirationcollapsing said blocking valve to isolate said bladder from the sourceof air at pressure lower than that of said respiration air whereby therespiration air flowing to the patients lungs exerts a pressure on theoutside of said bladder at the end nearest the lugs to thereby forcesaid bladder into tightening engagement with said trachea, said blockingvalve becoming inflated during expiration when the pressure of saidrespiration air is released whereby said air at a pressure lower thanthat of said respiration air can flow to said bladder to enlarge sameagainst the patients trachea.

2. The respiratory catheter of claim 1, further comprising a T-shapedfitting on the entry end of said tube, said fitting having one branchreceived in said tube, another branch closed off with a plug, and athird branch serving as an inlet for respiration air, said blockingvalve being disposed in said third branch.

3. The respiratory catheter of claim 2 wherein said blocking valve iscomprised of a pair of foil sheets connected together along their rimsto form an inflatablecollapsible structure.

References Cited UNITED STATES PATENTS 3,087,493 4/1963 Schossow 128-3513,211,152 10/1965 Stern 128-351 3,407,817 10/1968 Galleher 128-351 OTHERREFERENCES Martinez: Jour. Thoracic and Card. Surg., vol. 47, #3, March1964, pp. 404405.

' DALTON L. TRULUCK, Primary Examiner US. Cl. X.R. 128-208 UNITED STATESPATENT OFFICE CERTIFICATE OF CQRRECTION Patent No. 3 ,504, 676 DatedApril 7 1970 Inv Vagn Niels Finsen Lomholt It is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

Column 1, line 43, "construction" should read --constriction--; Column1, line 51, "construction" should read --constriction--; Column 1, lines60 and 61, after "trachea" on line 60,

"during both the inspiratory and exspiratory sure." should read--amounting to the maximum respiratory pressure. Column 1, line 71,"phase" should read --phases--..

Column 4, line 5, "in-flata-" should read --inflata---; Column 4, line17, "lugs" should read --lungs--.

3|GNER Nib SEALED SEPIEIQYD Edward x. mm Ir.

Attesting Officer VIII-LIAM 2. sum, JR- Gomissioner of Patents

